The present invention is drawn to a rear transmission device of a vehicle having a transversely mounted engine and four driven wheels of the type comprising a box including a housing through which the drive to the rear wheels is transmitted, mechanically coupled to a power unit, a rear differential having a housing and a longitudinal transmission shaft joining the housings.
It is known that in vehicles having a transversely mounted engine and four driven wheels, the box through which power is transmitted to the rear wheels is generally integral with the power unit and oscillates with the latter. This necessitates the provision of a longitudinal transmission consisting of a broken shaft and several transmission joints with slides (universal joints).
Moreover, the length of this transmission necessitates mounting intermediate bearings fixed to the floor, so as not to exceed the authorized critical speeds.
This assembly has the following drawbacks:
significant bulk (joints, bearings), PA1 cumbersome assembly (transmission joints and slides), PA1 difficulty of isolating noises inside the vehicle at bearing connections, PA1 difficulty of guaranteeing reliability over time (leak-tightness, greasing).
On the other hand, European Patent 0 160 188 discloses a transmission device in which the box for transmitting power to the rear wheels is articulated on the power unit about a transverse axis and the longitudinal tube for transmitting power to the rear is formed in articulated sections.
German Patent 650 692 discloses a transmission device provided with a rigid tube connecting the power unit and the rear axle, with which it forms a rigid assembly. As a result, the connection tube bears a part of the motor weight, and must therefore be very robust and have a large diameter in order to be able to withstand flexion forces.